Tumour infiltrating lymphocytes and PD-L1 expression as potential predictors of outcome in patients with malignant pleural mesothelioma

N. Sobhani, G. Roviello, T. Pivetta, A. Ianza, D. Bonazza, F. Zanconati, F. Giudici, C. Bottin, S. P. Corona, A. Guglielmi, C. Rizzardi, M. Milione, M. Cortale, M. Confalonieri, D. Generali

Research output: Contribution to journalArticlepeer-review


Malignant pleural mesothelioma (MPM) is a rare and aggressive form of tumour. Some mesotheliomas have been proven to be highly immunogenic. Here, we investigated the correlation between tumour infiltrating lymphocytes (TILs) or programmed cell death ligand 1 (PD-L1) expression with overall survival (OS) in patients with MPM. 62 Paraffin-embedded formalin fixed (PEFF) samples were analysed for TILs and PD-L1 expression. Patients were divided in 4 groups according to a cut-off of the percentage of TILs found per sample as measured by immunohistichemistry: “0” or absent (between 0 and 5%), “1” or low (between 6 and 25%), “2” or moderate (between 26 and 50%) and “3” or high (between 51 and 75%). OS was then correlated with different TILs’ expression patterns. Moreover, PD-L1 expression was assessed within the tumour as well as in the adjacent stroma on the same samples. Higher expression of peritumoral TILs (Group 2 + 3) versus Group 0 and 1 correlated with improved OS (p-value = 0.02). On the contrary PD-L1 expression seemed to be inversely correlated with clinical outcomes, even in the absence of statistical significance (HR 1.76; p = 0.083 95% IC 0.92–3.36 in areas within the tumour; HR 1.60; p = 0.176 95%; IC 0.80–3.19 in areas within the stroma). No relationship between TILs and PD-L1 expression was identified. Our research supports the use of TILs and PD-L1 expression as potential outcome predictors in patients with MPM. The use of TILs and PD-L1 as biomarkers for checkpoint inhibitors’ efficacy warrants future investigation.

Original languageEnglish
Pages (from-to)2713-2720
Number of pages8
JournalMolecular Biology Reports
Issue number3
Publication statusPublished - Jun 1 2019


  • Immunotherapy
  • Malignant pleural mesothelioma
  • Programmed cell death-ligand 1
  • Tumour-infiltrating lymphocytes

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics


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